Novel High Thermal Conductivity Substrates for GaN Electronics: Thermal Innovation

This programme will result in a step change in heat extracting substrates for GaN electronics, for GaN RF and for GaN power electronics. This transformative substrate development will enable these strategically important novel devices to operate at higher power levels and with increased device reliability for applications in future power conditioning in the low carbon economy, and for high efficiency communication and radar systems. The main objectives of the proposal are:

(i) Development of GaN-Si-polycrystalline substrates to compete with GaN-on-SiC for RF applications.
(ii) Development of GaN-metal substrates to compete with GaN-on-Si for power applications.
(iii) Development of innovative thermal analysis developments to support and enable the novel substrate development.
(iv) Demonstration of thermally improved HEMTs on the novel substrates.

With the UK's strength in RF and in power electronics, in academia and in industry, the outcomes of this programme have great potential for the UK to become a leader in achieving ultra-high power RF and power electronics, one of the key present international challenges in GaN electronics, as illustrated in the DARPA NJTT programme and the very recent ICECool BAA (www.grants.gov).

High power electronic devices inherently become hot during their operation. As they do so, they become increasingly inefficient and their function in an electronic circuit degrades, sometimes critically so. Yet societal demands to reduce greenhouse emissions has lead to a parallel demand for more efficient high power electronic devices in both traditional applications like power amplifiers and electrical motor controls and in new applications like the electronics needed for hybrid and all-electric road vehicles. These considerations have led to a growing world-wide interest in technologies that allow high power electronics, especially of the type used in radio and microwave systems like the mobile telephone networks, to operate at higher temperatures without active cooling like energy-hungry electrical fans. If such electronic devices could also be formed on materials that efficiently conduct the heat away then even further improvements in energy efficiency could be realised. The goal of this project is to combine transistors made from gallium nitride, a material that enables efficienct device operation at higher temperatures than their silicon based equivalents, with heat-extracting materials like copper or even diamond.